Effectiveness of Monovalent Rotavirus Vaccine After Programmatic Implementation in Botswana: A Multisite Prospective...

Area of Science:

• Public Health
• Vaccinology
• Pediatrics

Background:

• Botswana implemented the monovalent G1P rotavirus vaccine (RV1) in 2012, offering a crucial real-world assessment in a high-burden African setting.
• This study evaluated the effectiveness of routine RV1 vaccination against rotavirus diarrhea hospitalizations.

Purpose of the Study:

• To determine the effectiveness of the monovalent G1P rotavirus vaccine (RV1) in preventing rotavirus diarrhea hospitalizations in Botswana.
• To assess the impact of undernutrition on vaccine effectiveness in a resource-limited context.

Main Methods:

• A case-control study was conducted involving children under 5 years old admitted with diarrhea at four hospitals in Botswana between June 2013 and April 2015.
• Vaccine effectiveness (VE) was calculated by comparing vaccination histories of laboratory-confirmed rotavirus cases with non-rotavirus diarrhea controls using logistic regression.
• Genotyping identified circulating rotavirus strains, including the G2P type.

Main Results:

• The full series (2 doses) of RV1 showed 54% effectiveness against rotavirus diarrhea hospitalization, with one dose showing 48% effectiveness.
• Effectiveness against the common G2P genotype was 59%.
• Vaccine effectiveness was significantly higher in children without undernutrition (75%) compared to those with moderate or severe undernutrition (-28%).

Conclusions:

• Routine RV1 vaccination in Botswana is effective, with results comparable to clinical trials in Africa.
• The vaccine demonstrated effectiveness even against a serotype different from the vaccine strain.
• Undernutrition may partially explain reduced rotavirus vaccine effectiveness in low-income settings.